Method and apparatus for making spark plugs



Oct. 15, 1929. I T. w. WARREN .METHOD AND APPARATUS FOR MAKING SPARK'PLUGSI Filed Aug. 29, 1924 2 Sheets-Sheet 1 MIN l WWW INVENTOR BY 4 Mai ATTORNEY.

Get. '15, 1929. w WARREN METHOD AND APPARATUS FOR MAKING SPARK PLUGS Filed Aug. 29, 1924 2 Sheets-Shet 2 THOMAS WILLIIAM WARREN INVENTOR ATTORNEY Patented Oct. 15, 1929 UNITED ST TES PATENT OFFICE THOMAS WILLIAM WARREN, or MONTREAL, ouEEEo, CANADA METHOD AND APPARATUS FOR MAKING SI ARK PLUGS Application filed August 29, 1924, Serial No.

eration for making an improvedform of spark plug.

The invention more particularly concerns the making of spark plugs in which the core is of a material that is moulded into position and forinwhile in a molten condition.

I am aware that spark plugs with glass cores have been known and used but that owing to the method of manufacture and apparatus employed, such plugs are not free trom weakness, liability to injury, and failure. hereas the plug which is the result of my invention is of simple and durable construction, efficient. operation and cheap and rapid manufacture. A special feature of my invention is that it turns out by its operation a practically complete spark plug which does not necessitate additional operations to prepare it for the market. Except for-the binding post nut there are no loose parts, gaskets or adjustable fittings.

Reference is made to the annexed drawings in which: Figure 1 is a vertical cross section through the axis of the mould showing the inner face of one of the cover sections and the support with electrode and casing in moulding position. the support in a vertical position with the electrode and casing thereon.

' Figure 2 is a plan view of the mould with the top sections opened outwards.

Figure 3 is a vertical cross section the line 3-3 of Figure 1.

Figure 4 is a vertical cross section showing the molten glass pressed into the mould.

Figure 5 shows the spark plug immediately through v after removal from the mould.

The mould comprises a base 1, and a top comprising the parts 2 and- 3, hinged at 10 with interlocking projections 21 and 31 and bevelled side locks 22 and 32 which mesh when closed with the bevelled side locks 12 and 13 of the base 1. A locking pin 230 secures the mould in locked position.

The surface of the base 1 is shaped to receive one-half of a spark plug and of the sup The dotted lines show 734,997, and in Canada September 21, i923.

port. 4, and to form a seat for the casing 5 and the cap 62 and top 61 of the electrode 6. In the middle of the upper parts 2 and 3 is the feed cup 7 with central passage 71lead ing to the interior of the mould.

A plunger. 8 with compression rings 80, 81',

reciprocates from above.

The support 4 has a projection 41, which is centrally bored at 42 to receive the electrode 6, and an annular seat 43 to receive the lower rim 53 of the casing 5.

The support 4 is hinged at 44 to the base 1 permitting it to swing to a vertical position when the mould is opened, and to be removed if desired.

The projection 41 is shaped to mould the recess in the bottom ofthe core. 1

The electrode 6 employed in the form of spark plug shown consists of a screw threaded top 61 to receive a binding post thumb nut, an inverted cap 62 welded to the electrode, an asbestos wrapped portion 63, a central portion 64, an enlarged portion 65 and a split tip 66. 4

The casing 5 has an aperture 51 in its wall corresponding in size with the passage 71 from the feed cup 7.

The upper edge 52 of the casing 5 is turned in and while the lowerrim 53 is machined, the interior 54 of the casing is left rough and is not machined.

The casing 5 has the usual hexagonal sur- I face 55 and threaded portion 56.

The proper quantit of molten core material is fed into the eed cup 7 by suitable means.

The method ofop'eration is as follows:

- The mould is opened by swinging the upper sections 2 and 3 outwardly, the hinged support 4 is turned upwards and an electrode 6 s set in its bore 42. A casing 5 is then slipped over the top of the electrode 6 and placed on the annular seat 43 and the support bearing the electrode and casing is then adjusted, the casing sitting in the bottom of the mould wlth its aperture 51 upwards and the top 6 1 of the electrode 6 and the cap 62 sitting 1n their seats in the bottom of the mould. The top sections 2 and 3 are then closed and locked by the pin 230. The molten glass is fed into the cup 7 in the proper quantity and the plunger 8 descends into the cup 7 and presses the glass around the wall of the cup 7. The central portion of the glass which is at a high temperature then is pressed through the outlet 71 and aperture 51 and fillsthe mould and easing 5. By using high pressure the glass is forced around the electrode in complete contact with the inner wall of the casing. The

10 glass inentering the casing strikes the electrode and raises it to a high temperature which results in complete contact and eliminates occluded gases from the surface of the electrode.

The mould is immediately opened and the completed plug with attached glass cup 92 is swung upwards and removed from the support 4. v

The glass 91 protruding from the aperture 51 is then removed. Annealing may then take place. The binding post nuts are then screwed on the top of the electrode and the lower split end is bent outwardly.

It will thus be seen that the core 9 is formed and set securely in position by one operation and that the electrode 6 and casing 5 are firmly bonded by the core 9 into one compact whole.

What I claim is 1. An apparatus for making spark plugs comprising a mould, a horizontal base thereto, a seat cut therein to receive one axial half of the spark plug, a supporthinged to one end of the base, a central bore in the support, an

annular seat on the support, a two part top to the mould hinged vertically at one end of the base, a locking means to the top part and base, a quarter seat cut in each part of the top, a cylindrical cu in the top of the mould 4,0 one half out in eac part thereof, a central bore from the bottom, of the. cup to the interior of the mould, a plunger with compression rings adapted to reciprocate vertically and enter the cup and to compress molten insulating material in the cup into the mould.

2. In an apparatus for making spark plugs a horizontal mould, a support hinged thereto adapted to receive the casing and electrode in a vertical position and to swing and adjust the supported parts in the mould in a horizontal position. 5

3. In an apparatus for making spark plugs a horizontal mould, a support hinged thereto and forming one end of the mould, adapted to receive the casing and electrode While in a vertical position and when swung to a horizontal position to adjust the supported parts within the mould.

THOMAS WILLIAM WARREN. 

